Swift 3：如何缩放和旋转UIImageView？

我真的很难在网上找到教程以及已经回答的问题(我已经尝试了它们,但它们似乎不起作用).我有一个UI ImageView,我在我的视图中心.我现在能够在屏幕上点击并拖动它.我希望能够缩放并旋转此视图.我该如何实现这一目标？我已经尝试过下面的旋转代码,但它似乎不起作用？任何帮助都将是一个巨大的帮助,并标记为答案.感谢你们.

import UIKit

class DraggableImage: UIImageView {

    override func touchesBegan(_ touches: Set<UITouch>,with event: UIEvent?) {

        self.backgroundColor = .blue

    }

    override func touchesEnded(_ touches: Set<UITouch>,with event: UIEvent?) {

        self.backgroundColor = .green

    }

    override func touchesMoved(_ touches: Set<UITouch>,with event: UIEvent?) {
        if let touch = touches.first {
            let position = touch.location(in: superview)
            center = CGPoint(x: position.x,y: position.y)
        }
    }

}

class CVController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        view.backgroundColor = .white

        let rotateGesture = UIRotationGestureRecognizer(target: self,action: #selector(rotateAction(sender:)))
        firstimageView.addGestureRecognizer(rotateGesture)

        setupViews()
    }

    func rotateAction(sender: UIRotationGestureRecognizer) {
        let rotatePoint = sender.location(in: view)
        let firstimageView = view.hitTest(rotatePoint,with: nil)
        firstimageView?.transform = (firstimageView?.transform.rotated(by: sender.rotation))!
        sender.rotation = 0
    }

    let firstimageView: DraggableImage = {
        let iv = DraggableImage()
        iv.backgroundColor = .red
        iv.isUserInteractionEnabled = true
        return iv
    }()

    func setupViews() {
        view.addSubview(firstimageView)

        let firstimageWidth: CGFloat = 50
        let firstimageHeight: CGFloat = 50

        firstimageView.frame = CGRect(x: (view.frame.width / 2) - firstimageWidth / 2,y: (view.frame.height / 2) - firstimageWidth / 2,width: firstimageWidth,height: firstimageHeight)
    }

}

您的代码中存在一些问题.首先,您需要将UIGestureRecognizerDelegate添加到视图控制器,并将其设置为手势识别器委托.并添加shouldRecognizeSimultaneously方法并返回true.第二,当应用比例时,您需要在捏开始时保存变换并在其顶部应用比例：

class DraggableImageView: UIImageView {
    override func touchesBegan(_ touches: Set<UITouch>,with event: UIEvent?) {
        backgroundColor = .blue
    }
    override func touchesEnded(_ touches: Set<UITouch>,with event: UIEvent?) {
        backgroundColor = .green
    }
    override func touchesMoved(_ touches: Set<UITouch>,with event: UIEvent?) {
        if let position = touches.first?.location(in: superview){
            center = position
        }
    }
}

class ViewController: UIViewController,UIGestureRecognizerDelegate {

    var identity = CGAffineTransform.identity

    override func viewDidLoad() {
        super.viewDidLoad()
        view.backgroundColor = .white
        setupViews()

        let pinchGesture = UIPinchGestureRecognizer(target: self,action: #selector(scale))
        let rotationGesture = UIRotationGestureRecognizer(target: self,action: #selector(rotate))

        pinchGesture.delegate = self
        rotationGesture.delegate = self

        view.addGestureRecognizer(pinchGesture)
        view.addGestureRecognizer(rotationGesture)
    }
    let firstimageView: DraggableImageView = {
        let iv = DraggableImageView()
        iv.backgroundColor = .red
        iv.isUserInteractionEnabled = true
        return iv
    }()

    func setupViews() {
        view.addSubview(firstimageView)
        let firstimageWidth: CGFloat = 50
        let firstimageHeight: CGFloat = 50
        firstimageView.frame = CGRect(x: view.frame.midX - firstimageWidth / 2,y: view.frame.midY - firstimageWidth / 2,height: firstimageHeight)
    }
    func scale(_ gesture: UIPinchGestureRecognizer) {
        switch gesture.state {
        case .began:
            identity = firstimageView.transform
        case .changed,.ended:
            firstimageView.transform = identity.scaledBy(x: gesture.scale,y: gesture.scale)
        case .cancelled:
            break
        default:
            break
        }
    }
    func rotate(_ gesture: UIRotationGestureRecognizer) {
        firstimageView.transform = firstimageView.transform.rotated(by: gesture.rotation)
    }
    func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer,shouldRecognizeSimultaneouslyWith otherGestureRecognizer: UIGestureRecognizer) -> Bool {
        return true
    }
}